The equation of a wave travelling in a string can be written as $y = 3\cos \pi (100t - x)$. Its wavelength is .... $cm$.

$A$ boat at anchor is rocked by waves whose crests are $100 \,m$ apart and velocity is $25 \,m/s$. The boat bounces up once in every (in $\,s$)

$A$ sound of frequency $480 \,Hz$ is emitted from a stringed instrument. The velocity of sound in air is $320 \,m/s$. After completing $180$ vibrations, the distance covered by the wave is: (in $\,m$)

$A$ wave travels uniformly in all directions from a point source in an isotropic medium. The displacement of the medium at any point at a distance $r$ from the source may be represented by ($A$ is a constant representing strength of source)

$A$ transverse wave $Y=2 \sin (0.01 x+30 t)$ moves on a stretched string from one end to another end in $0.5 \ s$. If $x$ and $y$ are in $cm$ and $t$ in $s$,then the length of the string is: (in $m$)

The equation of a plane progressive wave is given by $y = 0.025 \sin (100t + 0.25x)$. The frequency of this wave would be